Rechargeable secondary batteries are widely utilized in portable devices, tools, uninterruptible power supplies, etc. In particular, wireless communication techniques are receiving attention as power sources for portable devices and the like.
With the recent advancement of mobile devices, cable-type secondary batteries, the shape of which may be freely changed, are required these days. The process of manufacturing a cable-type secondary battery includes welding a metal tap to an electrode layer for a cable-type secondary battery. However, the cable-type secondary battery is problematic because an insulating layer and a conductive layer formed on the electrode layer are made of a polymer material, and thus, weld quality resulting from typical welding of the electrode layer may become poor.
With the goal of solving such problems, for example, Korean Patent Application Publication No. 10-2013-0040552 discloses that slippage between an electrode part and a terminal part is minimized, thus facilitating weld bonding and increasing welding performance. However, even when this technique is applied to the welding of the metal tab and the electrode layer for a cable-type secondary battery, the improvement of the weld quality is limited.